Anticipating room thermostat



Patented Sept. v7, 1937 PATENT .OFFICE 2,092,327 Y ANTICIPATING ROQM THERMOSTAT Lawrence M. Persons, Des Moines, Iowa, assignor to Penn Electric Switch Co., Des Moines, Iowa,

a corporation ot Iowa Application 29, 1935, Serial No. 18,744

, l s claims. (cl. zoo- 122) An object of my invention is` to provide a heater for an anticipating type of room thermostat, the heater being comparatively simple and inexpensive as well as durable.

. A further object is to provide ananticipating room thermostat heater unitreadily connectible with terminals of a room thermostat of the type shown for instance in my co-pending application Serial No. 744,156, led September 15, 1934, now Patent #2,040,404, issued May 12,1936, the heater being variable in effect so that one heater can bev used for all diierent installations. In this connection it may be mentionedy that anticipating room thermostats must be designed for use with all types Aand sizes of fuel burners. Fuel burners have different ratings and consequently require differentamounts of electric current for controlling them. Each room thermostat installation of an anticipating type must have the proper size of heater to secure the necessary anticipation feature without over or under anticlpation and heretofore it has been customary to Aprovide heater elements of different sizes or capacity, the dealer installing the burner placing the proper one in a given installation. My present invention contemplates, as one object thereof, the provision of a single heater the effect of which can be varied by connecting more ory less of the heater Wire in circuit.

With these and other objects in view my invention consists in the Vconstruction, arrangement and combination of the various parts of Y my device, whereby the objects contemplated are attained, as hereinafter 'more fully set'forth, pointed out in my claims and illustrated in the accompanying drawing, in'which:

y Figure 1 is a front elevation of a room thermovstate showing my variable anticipator unit installed therein. y y

Figure -2 is a sectional view on the line 2-2 of Figure 1 showing the relation of the heater to the temperature responsive element `or room thermostat.. j

, Figure 3 is a detail sectional view o'n the line 3-3 of Figure 1 showing the heater unit only.

Figure 4 is a bottom plan view of the heater unit only; Y. l

Figure 5 is a sectional view on the line 5 5 of Figure 4; and

Figure 6 is an electro-diagrammatic view showing the room thermostat and my anticipating heater in a burner circuit. 1

On the accompanyingfdrawing, I have used ,the reference numeral d lll to indicate a switch casing of a room thermostat. Mounted within the casing I0 is a bimetal element l2 of zig-zag shape anchored at one end by rivets Il and having an armature I6 secured to its other end. The armature carries a contact I8 cooperable with a contact 20, these `contacts being adapted for 5 connection in the circuit of a fuel burner, the motor of which is indicated at M in Figure 6, 'I'he room thermostat includes a pair of terminal straps'22 and 2l to which heretofore interchangeable antcipator heating elements have been se- 10 cured by terminal screws 26 and 28 respectively. My present invention is an anticipating heater unit indicated generally by the character A secured electrically in the circuit and mounted by the terminal screws 2G and 28.

As to the specific construction of the unit A it comprises a core member 30, preferably of insulating material having a pair of plates 32 and 34 riveted theretoV by tubular rivets 3B and 38 respectively. The rivets 36 and 3B form termil0 nals through which the screws 26 and 28 extend.

'Ihe plates 32 and 3l are held against rotation relative to the rivets 38 and 38 by anges lll and 42. An ear. (see Figure 4) is also bent over an extension 20a of the core to retain the parts 25 inr assembled position- 'Wound on the core Il is a resistance wir 46. 'I'he ends thereof, indicated at I8 and 50, are soldered to terminal lugs 52 and 5I formed on the plates 32 and 34 respectively. y f

A short circuiting lever 56 is provided having one end pivotally mounted by a rivet 58 on the plate 32'and its other end carrying a contact button GII for contact with the resistance wire I6.

The lever 56 can be swung for cutting out more 35,

or less-of the resistance wire.

Suitable indicia such as 1, 2, 3, 4 and 5 shorter and 1onger" areprovlded on the plate 32 for convenienceof the person installing the room thermostat.

Shorter" refers to shorter periods of operation or, in other-words, a greater degree of anticipation and likewise longer refers to a lesser degree of anticipation/which can be determined by actually operating the burner after the room thermostat is installed and noting its periods of operation. i

j Initially, of course, the lever 58 is set at the proper point, depending on the current consumption of the particular installation. This is much easier to accomplish than by changing the heater element as has been done heretofore. Also after the burner has been in operation, th

degree of anticipation can be changed by merely shifting the liever B6 without having to remove a BISv heater element and install another one of a different capacity.

Th end Q8 of the resistance wire Q6 need not necessarily be connected with the plate 32 as any wire between the button 60 and the terminal lug 52 is shorted out of the circuit. However, I prefer such a connection so that if the button 60 becomes dirty and does not let the current pass through, the burner can still operate although the degree of anticipation will be thrown off and of course have to be corrected. Until such time las it is corrected, however, the burner can continue to operate.

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention and it is my intention to cover by my claims any modied forms of structure or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

1. An anticipating room thermostat comprising a temperature responsive element, contacts controlled thereby, a pair of terminals in series circuit with said contacts and an anticipating heater for said temperature responsive element comprising aninsulating member, a heating element wound thereon, a pair of terminal plates, tubular rivets for connecting said terminal plates to said insulating member with the terminal plates spaced relative to each other, said tubular rivets being spaced a distance equal to the distance between said terminals and adapted to reiceive them, one end of said heating element being a temperature responsive element, contacts controlled thereby, a pair offterminals in series circuit with said contacts and an anticipating heater for said temperature responsive element comprising an insulating member, a heating element wound thereon, a pair of terminal plates,

tubular rivets for connecting said terminal plates to said insulating member with the terminal plates spaced relative to each other, said tubular rivets being spaced a distance equal to the distance between said terminals and adapted to receive them, the ends of said heating element being connected to said terminal plates and a contact lever pivoted to one of said terminal plates tubular rivets for connecting said terminal plates 1 LAWRENCE M. PERSONS. 

